ML20217F928
| ML20217F928 | |
| Person / Time | |
|---|---|
| Site: | Pilgrim |
| Issue date: | 03/26/1998 |
| From: | Oheim H BOSTON EDISON CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| Shared Package | |
| ML20217F933 | List: |
| References | |
| 2.98.030, TAC-M95277, NUDOCS 9804010300 | |
| Download: ML20217F928 (11) | |
Text
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%m Pilgran Nuclear Power Station Rocky Hill Road Plyrnouth, Massachusetts 02360 Hawy V. Ohobn General Manager Technical Section March 26,1998 BECo Ltr. #2.98.030 US Nuclear Regulatory Commission Attention: Document Control Desk l
Washington, DC 20555 Docket No. 50-293 License No. DPR-35 Supplement to Emergency Diesel Generator Allowed Outane Time Technical Specification Chance (TAC No. M95277)
References
- 1. Boston Edison Company Letter No.96-040, Proposed Technical Specification Changes," dated April 25,1996.
- 2. Boston Edison Company Letter No.96-080, Response to Request For Additional !
Information Regarding Emergency Diesel Generator Allowed Outage Time Technical Specification Change," dated September 5,1996.
- 3. Boston Edison Company Letter No.97-082, Supplement to Emergency Diesel Generator Alfowed Outage Time Technical Specification Change (TAC No. M95277)"
dated August 8,1997.
Boston Edison Company (BECo) hereby provides additional information in suppod of the proposed Technical Specification (TS) change for the emergency diesel generator (EDG) allowed outage time (AOT) submitted on April 25,1996 (Ref.1).
- 1. Attachment A provides clarifications to our previous responses (Refs. 2 and 3) as discussed during NRC/BECo telephone calls made on September 24,1997.
- 2. Attachment B provides the revised no significant hazards consideration determination pursuant to 10 CFR 50.92(c) taking into consideration the NRC required verification of station blackout diesel generator (SBO-DG) operability before entering into an extended EDG AOT. The 'no significant hazards consideration determination for proposed revisions to Specifications 3.9.B.1 and 3.9.B.4 are restated to reflect the complete EDG AOT TS change package. This determinadon supersedes the previous determination included in our proposed TS change letter dated April 25,1996 (Ref.1).
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- 3. Attachment C includes revised TS pages 3/4.5-7 and 83/4.5-6 requiring verification of
. . SBO-DG operability before entering into an extended EDG AOT. The revised pages incorporate the NRC's request to include the SBO-DG in the TS and comments related to SBO-DG surveillance provided during the September 24, 1997, telephone call.
Additionally, a reformatted TS Section 3.9 with revisions to Specifications 3.9.B.1 and 3.9.B.4 as submitted in Ref.1 are included to provide a complete EDG AOT TS change package.for NRC approval.
Should you have any questions regarding this letter, p; ease contact Walter Lobo at (508) 830- '
7940.-
.- Aw H. V. Oheim WGL/dcg 298029 Attachment A: BECo Response to NRC Request for Additional Information Attachment B: Revised No Significant Hazard Consideration Determination Attachment C: Revised T.S. Pages and Bases Applicable for EDG AOT cc: Mr. Alan B. Wang, Project Manager Mr. Robert Hallisey Project Directorate 1-3 Radiation Control Program Office of Nuclear Reactor Regulation Center for Communicable Diseases Mail Stop: OWFN 14B2 Mass. Dept. of Public Health 1 White Flint North 305 South Street 11555 Rockville Pike Jamaica Plain, MA 02130 Rockville, MD 20852 U.S. Nuclear Regulatory Commission Mr. Peter LaPorte, Director Region i Mass. Energy Management Agency 475 Allendale Road 400 Worcester Road King of Prussia, PA 19406 P.O. Box 1496 Framingham, MA 01701-0313 Senior Resident inspector Pilgrim Nuclear Power Station l
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ATTACHMENT A BECo Response to NRC Reouest for Additionalinformation EDG AOT Technica' Specification Chance (TAC No. M95277) hfarences
- 1. Boston Edison Company' Letter No.96-040, " Proposed Technical Specification
! Changes," dated April 25,1996.
- 2. Boston Edison Company Letter No.96-080, " Response to Request For Additional Information Regarding Emergency Diesel Generator Allowed Outage Time Technical Specification Change," dated September 5,1996.
- 3. Boston Edison Company Letter No.97-082, " Supplement to Emergency Diesel Generator Allowed Outage Time Technical Specification Change (TAC No.
M95277)", dated August 8,1997.
B_ackaround BECo' filed a request (Ref.1) for an EDG TS change to extend the current AOT from 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> to.14 days. Subsequently, BECo provided additional information (Refs. 2 and 3) in ,
response to NRC requests for additional information. On September 24,1997, BECo and l NRC staff discussed the proposed TS change, issues related to EDG maintenance practices, and our previous responses (Refs. 2 and 3). This attachment addresses the issues raised by the NRC.
- 1. Load Reiection Test j
- Ref.- 2 (Question 3.b response) stated that "... full load rejection tests are not routinely l performed on EDGs at PNPS. However, following postulated replacement of a govemor l (during current normal operation [LCO] or an [ plant] outage), some form of load rejection- !
- testing would likely be performed.". Whereas, Ref. 3 (item D) stated that " a full load rejection test will not be performed on-line." The NRC staff reviewer requested clarification of these statements regarding the load rejection test. Also, in the event of performing any work on-line during an LCO, the reviewer asked what assurances BECo has there will not be any damage to our electrical buses as a result of improperly performed maintenance. !
Our clarification regarding load rejection testing and post work testing is as follows:
Our response is as stated in Ref. 3. A full load rejection test will not be performed on-line.
Further, during our discussion on September 24, 1997, we attempted to describe steps involved in the post work testing (PWT) process following maintenance work to fully respond ;
to the NRC's question conceming assurances we will not cause any damage to buses as_a result of improperly performed maintenance. As an example, we have used a full load rejection test following a postulated govemor replacement maintenance to' illustrate the steps involved in PWT.
- At.PNPS, full disassembly of the EDG is not within the scope of procedure 3.M.3-61.5,
~ " Emergency Diesel Generator Refuel- Outage Preventive Maintenance" . The bulk of the procedure relates to the inspection of the condition of the EDG to look for signs of wom gears, excessive leaking of oil'or degraded conditions. During PWT of any work performed Page1 of4
on the EDGs, the level of PWT is determined by the extent of the maintenance work done.
, Repetitive _ work that is commonly done may already have the PWT specified in the current procedures and past work plans. Improper maintenance would be detected during PWT prior to exiting the EDG LCO. The potential for damage to other equipment is minimized by the progressive steps in the PWT process.
J Work that is not commonly performed is reviewed by the system engineer, and the level of f PWT is determined by the type of work that is being done. The PWT steps are described below.
(i). Preliminary Testing: After the prescribed work is performed, the first stage of PWT ,
would be called preliminary testing. This testing includes any checks that can be performed while the system is in a static conditien, tagged out, with the diesel still inoperable. Anything {
from fluid levels to point-to-point wire checks and any vendor-specified checks would be performed during this time. This work would be specified in the work plan.
(ii). Functional Testing: The next step would be functional testing. Included in this phase would be energized checks or any simulated testing that can be performed without starting I the EDG. Examples would be control circuit checks and running motors for vibration. For a {
governor change out, we would check the condition of the EDG and its ability to supply the proper signal to the mechanical governor.
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(iii). Pre-operational Testing: The next step would be the pre-operational test phase. In this step we would operate the system without letting it interact with the rest of the station
'(e.g., diesel generator would be isolated from the safety bus). For a govemor change out, we would check the engine unloaded to verify all air was purged from the govemor system
- and bleed it if necessary. We would verify the ability to control speed from all locations. An attachment in procedure 3.M.3-61.2, " Emergency Diesel Generator General and Preventive Maintenance Corrective Actions", exists that would allow us to perform a test of the speed control and voltage control. Both tests would be done in this instance because speed control problems can also affect voltage control.
(iv). Operational Test: The next test would be the operational test. In this case, the procedure used would be 8.9.1, " Manually Start and Load the EDGs". In this test, the machine would be started and checked prior to loading onto the grid via an emergency bus.
This procedure contains conservative ABORT criteria. The purpose of this criteria is to protect the equipment ( EDG and connected equipment).
(v). Load Rejection Test: The next step, if necessary, would be a load reject test. In order to do this, a temporary procedure would be written which would require the standard reviews of a proposed test including a determination if a 10 CFR 50.59 evaluation is required, technical review, quality control, and operations review committee approvals.
.The above is only an example of what might be done to address PWT. The philosophy behind PWT is to minimize the risk in damaging any equipment. These steps ensure the i component and system are functional. Any problems found would be corrected before proceeding to the next level of testing.
- The above approach ensures we will not cause damage to the emergency buses and associated connecting equipment as a result of improperly performed maintenance.
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- 2. Breaker Confiauration and Reliability The NRC Staff requested breaker indication and reliability information for breakers which would be required to energize safety-related buses when ths SBO-DG is operable. Our response is as follows.
The breakers that interface between the SBO-DG,23Kv power sources, and 4160 volt buses A5 and A6 are 152-501,152-600,152-601,152-801 and 152-802. The configuration /
location of these breakers is shown in the attached figure, " Alternate AC Distribution System".
Breakers 152-501,152-600, and 152-601 are safety-related, and 152-801 and 152-802 are non safety-related. These breakers are included in the maintenance rule monitoring procedure. They have shown no failures during last three years. They have a good operating history and have proven to be highly reliable. They have position indication locally at the switchgear and in the control room. These breakers have spring charge indicator lights on the outside of the switchgear door to indicate that the breaker's closing springs are charged and the breaker is ready to function on a demand signal.
Breaker 152-501 is normally in the open position. It can be tripped (opened) locally and ir; the control room but can be manually closed only by the control room switch. This breaker will automatically close if the unit auxiliary transformer, startup transformer, and the "A" EDG are not available. Because this breaker can not be easily cycled, it has a rigorous maintenance schedule which includes preventive maintenance every two years and overhaul every six years. The bus transfer scheme for this breaker is tested once per cycle as required by technical specifications.
Breaker 152-600 is normally in the closed position. It can be tripped (opened) locally and in the control room but can be manually closed only by the control room switch. It is cycled during on-line shutdown transformer outages (at least once a year). It follows the maintenance schedule for safety-related breakers which can be cycled annually. This breaker undergoes preventive maintenance every four years and overhaul every eight years.
Breaker 152-601 is normally in the open position it can be tripped (opened) locally and in the control room but can be manually closed only by the control room switch. This breaker will automatically close if the unit auxiliary transformer, startup transformer, and the "B" EDG are not available. Because this breaker can not be easily cycled, it has a rigorous maintenance schadule which includes preventive maintenance every two years and overhaul every six years. The bus transfer scheme for this breaker is tested once per cycle as required by technical specifications.
Breaker 152-801 is normally in the open position. It can be controlled locally and in the control room. This breaker is cycled during quarterly SBO-DG surveillance. It follows the maintenance schedule for non safety-related breakers. This breaker undergoes preventive maintenance every four years and overhaul every eight years.
Breaker 152-802 is normally in the closed position. It can be controlled locally and in the control room. This breaker gets cycled during shutdown transformer outages (at least once a year). It follows the maintenance schedule for non safety-related breakers. This breaker undergoes preventive maintenance every four years and overhaul every eight years.
- 3. Modifications to the SBO-DG In response to Licensee Event Report 97-004-00, " Loss of Preferred Offsite Power and Oil Spi!! Due to Main Transformer Fault While Shutdown", dated April 7,1997 (BECo Letter No.
97-038A and NRC Inspection Report 97-02, item No. 02), we implemented (i) procedural Page 3 of 4
enhancements to provide guidance to operators regarding startup and operation of the SBO-DG unloaded and (ii) completed a plant design change, PDC 97-14, " Revised Power Supply for SBO Diesel Auxiliaries" to provide an alternate source of power to the SBO-DG auxiliaries j to ensure startup and availability of the SBO-DG during partial or degraded offsite power j conditions. The NRC staff requested BECo clarify the impact on the security diesel due to '
. supplying power to SBO-DG auxiliaries from the security diesel and the duration of the SBO-DG battery. Our response is as follows:
Under plant design change (PDC) 97-14, during a loss of offsite power conditions, J
approximately 58 kW will be supplied to the SBO-DG auxiliaries from the 400 kW security ;
diesel. This 58 kW will not impact the security diesel's ability to supply its required loads i because the current loading on the security diesel is approximately 256 kW, and there is i sufficient margin to add the additional 58 kW without challenging the security diesel ratings.
The SBO-DG battery is designed to carry the load for 7 hours8.101852e-5 days <br />0.00194 hours <br />1.157407e-5 weeks <br />2.6635e-6 months <br />. The SBO-DG battery charger is powered by the output of either the SBO-DG or security diesel.
- 4. Maintenance Rule Applicability for SBO-DG Eauipment The NRC staff requested clarification concerning the applicability of the Maintenance Rule to the SBO-DG and how SBO-DG performance is " administratively controlled". Our response is ,
as follows:
The SBO-DG is within the scope of the Maintenance Rule. Ref. 3 Table B describes the l
Maintenance Rule (10CFR50.65) performance criteria for the SBO-DG and provides the actual performance vs the criteria. Ref. 3 item C should have included the SBO-DG; it was ]
inadvertently omitted since item B described the applicability of Maintenance Rule for EDGs and SBO-DG, and the Maintenance Rule documentation is written for EDGs and includes SBO DG.
Ref. 3 item B states that the " performance" of the SBO-DG is " administratively controlled" and
" Performance can not degrade below the rule limits without implementation of corrective actions to restore performance to acceptable maintenance rule program criteria...."; that is, performance of SBO-DG is monitored against established criteria in accordance with the Maintenance Rulec We have procedures (NOP 95A4, "NRC Maintenance Ruie Procedure" and NESG 16.03, "10 CFR 50.65 NRC Maintenance Rule") in place that implement the requirements of the Maintenance Rule. These procedures instruct system eng'neers to establish performance criteria for their inscope systems, structures and components (SSCs) and to monitor the performance of the SSCs against the performance criteria, if actual SSC performance degrades such that the performance criteria is exceeded, the system engineer is required to evaluate the cause of the degraded performance and, if warranted, implement corrective actions to improve performance such that the performance criteria are again met.
Thus, SBO-DG performance can not degrade below the " administrative" limits imposed by the Maintenance Rule procedures without the system engineer knowing it and implementing corrective action. Hence, the term " administratively controlled" is used to control SBO-DG performance.
- 5. Confirmation of Previous Responses The NRC Staff requested BECo review the previous responses (Refs. 2 and 3) to state they are applicable for EDG AOT. Our response is as follows:
Except for the above items 1 to 4 as modifiod and clarified by this letter, the remaining responses in References 2 and 3 are applicable for the EDG TS change.
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(SECONDARY)
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ATTACHMENT B REVISED NO SIGNIFICANT HAZARD CONSIDERATION DETERMINATION Description of amendment reauest: The proposed amendmont would revise Technical Specifications (TSs) and associated Bases Section for TSs 3/4.5.F.1, " Core and Containment Cooling systems" and TSs 3.9.B.1 and 3.9.B.4, " Auxiliary Electrical System."
TS 3.5.F.1 is revised to extend the allowed outage time (AOT) for the emergency diesel generators (EDGs) from the currently allowed 3 days to 14 days. TS 4.5.F.2 is added to confirm that the station black out diesel generator (SBO-DG) is operable for extending the EDG AOT from 3 days to 14 days. The actions include confirmation that SBO-DG has been demonstrated operable within the preceding 7 days before extending the AOT from 3 days to 14 days or to perform a surveillance within 3 days of an EDG inoperability to demonstrate that the SBO-DG is operable. The SBO-DG is a non safety-related, manually started, 2000 KW generator and is not a qualified replacement for an EDG. An additional action is added to verify normal breaker configuration to ensure the SBO-DG is capable of energizing the safety bus associated with the inoperable EDG. These actions assure that one EDG and the SBO-DG are operable during an extended EDG AOT.
TS 3.9.B.1 is also split into two individual AOTs, one for the startup transformer (SUT) .
and one for the shutdown transformer (SDT). The AOT for SDT remains at 7 days (TS 3.9.B.1.b), and the AOT for the SUT.is reduced from 7 days to 3 days (TS 3.9.B.1.a) based upon the probabilistic safety assessment (PSA) results. TS 3.9.B.4 is revised to specify AOTs for the combination of an inoperable SUT or SDT and an inoperable EDG, The AOT for simultaneous inoperability of the SDT and an EDG is 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> (TS 3.9.B.4.a). The AOT for simultaneous inoperability of the SUT and an EDG is 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> (TS 3.9.B.4.b) . These changes in the AOTs for the SUT and SDT are proposed based upon their contribution to risk ;
in relation to the EDG 14-day AOT risk assessment analysis. Adding additional system l operability requirements to TS 3.9.B.4 provides a positive measure to prevent entry into or ]
remain in the 14-day EDG AOT, if the required offsite power supplies become unavailable.
Basis for oroposed no sionificant hazards consideration determination: The Code of i Federal Regulations,10 CFR 50.91(a), requires licensees requesting an amendment to !
provide an analysis, using the standards in 10 CFR 50.92, that determines whether a i significant hazards consideration exits. As required by 10 CFR 50.91(a), Boston Edison l Company provides the following analysis to determine no significant hazards consideration in i accordance with 10 CFR 50.92.
- 1. The proposed amendment does not involve a sianificant increase in the probability or conseauences of an accident previously evaluated. !
Operation of Pilgrim Nuclear Power Station in accordance with the proposed license amendment will not involve a significant increase in the probability or consequences of an i accident previously evaluated because of the following: i
~ An Individual Plant Examination (IPE) for Intemal Events was submitted to the NRC in ;
response to Generic Letter _88-20 in September 1992. The supporting probabilistic safety l analysis (PSA) model was updated as described in BECo letter 95-127, dated December 28, j 1995. The updated PSA model was used to quantify the overallimpact of the proposed EDG 14-day AOT on core damage frequency. Part Ill of BECo Letter No. 2.96.040 provides the i results of a comprehensive PSA of the impact of the proposed AOTs for the EDGs and SUT and SDT. As shown in Part 111, there is no significant increase in risk due to the proposed Page1of4
change. Thus, the proposed change does not involve a significant increase in the probability or consequences of an accident previously evaluated.
The existing specification 3.9.B.1 is separated into two segments (a and b) because of the proposed different AOTs for the SUT and SDT transformers. As a result of the PSA, the i AOT for the SUT _(a) is reduced from 7 days to 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />, while the AOT for the SDT (b) remains at 7 days. The reduction of the AOT from 7 days to 3 days is based on the relative risk importance of the SUT support to the balance of plant systems. Similarly, an adoitional reduction from 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> to 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> is proposed in the AOT for a simultaneous loss of both the SUT and an EDG (TS 3.9.B.4.b) based upon the SUT's contribution to risk and that two power sources have been removed from the associated bus. The AOT reductions represent a measurable decrease in risk as assessed in the PSA. Thus, the probability or consequences of an accident previously evaluated are not increased.
The current technical specifications allow one EDG to be out of service for three days based on the availability of the SUT and SDT and the fact that each EDG carries sufficient engineered safeguards equipment to cover all design basis accidents. Additionally, the SDT can provide adequate power for one train of ESF equipment for all operating, transient, and accident conditions. With one EDG out of service and a Loss of Offsite Power (LOOP) condition, the capability to power vital and auxiliary system components remains available via the other EDG. Increasing the EDG AOT to 14 days provides flexibility in the maintenance and repair of the EDGs. The EDG unavailability will be monitored and trended in accordance with the Maintenance Rule. The PSA analyses supports the change to a 14 day AOT for the EDGs based on an insignificant increase in overall risk. Implementation of the proposed change is expected to result in less than a one percent increase in the baseline core damage frequency (2.84E-05/yr), which is considered to be insignificant relative to the underlying uncertainties involved with PSA. An additional condition is added requiring the SBO-DG to remain operable for extending the inoperable EDG AOT from 3 days to 14 days, thereby assuring that one EDG and SBO-DG are available during the extended EDG AOT. Thus, the 14-day EDG AOT does not involve a increase in the probability or consequences of an accident previously evaluated.
The proposed change does not affect the design or performance of the EDGs, and the change will not result in a significant increase in the consequences or probability of 'an accident previously analyzed. These changes do not involve a increase in the probability or consequences of an accident previously analyzed.
- 2. The proposed amendment does not create the oossibility of a new or different kind of accident f'om any accident previously evaluated.
The operation of PNPS in accordance with the proposed license amendment will not create the possibility of a new or different kind of accident from any accident previously evaluated because of the following:
The proposed amendment will extend the action completion / allowed outage time for an inoperable EDG from 3 days to 14 days. During this extension, the SBO-DG is required to be operable and normal breaker configuration is required to be verified to ensure the SBO-DG is capable of energizing the safety bus associated with the inoperable EDG. These actions assure one EDG and SBO-DG are operable during extended EDG AOTs. The EDGs are designed as backup AC power sources for exential safety systems in the event of loss of offsite power. The SBO-DG is designed to cope with a station black out transient. The proposed AOT does not change the conditions, operating configurations, or minimum amount of operating equipment assumed in the safety analysis for accident mitigation. The EDGs, SBO-DG and AC equipment are not accident initiators. No change is being made in the Page 2 of 4 o _
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manner in which the EDGs provide plant protection. No new modes of plant operation are involved. An extended AOT for one EDG does not create a new or different kind of accident
_ previously evaluated. The PSA results concluded the risk contribution of the EDG AOT extension is insignificant.
Pilgrim has implemented an EDG reliability program to maintain reliability of EDGs. The SBO-DG is included in the reliability program, and the performance of EDGs and SBO-DG are trended for compliance with Maintenance Rule requirements. Thus, the proposed i change does not introduce any new mode of plant operation or new accident precursors,
-involve any physical alterations to plant configurations, or make changes to system set points that could initiate a new or different kind of accident. Therefore, operation in accordance with the proposed change does not create the possibility of a new or different kind of accident from any previously evaluated. l The AOT for an inoperable SUT is reduced from 7 days to 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> based upon the PSA that ;
was performed to quantitatively assess the risk impact of the proposed amendment. '
Additionally, removal of the SUT from service degrades the reliability of the offsite power system and renders the balance of plant unavailable upon a plant shutdown. The proposed reduction in AOT improves overall AC power source availability because the SUT will potentially be inoperable for shorter time periods. Therefore, reducing the AOT does not create the possibility of a new or different kind of accident from any accident previously evaluated.
- 3. The proposed amendment does not involve a sionificant reduction in a maroin of safety.
The operation of PNPS in accordance with the proposed license amendment will not involve a significant reduction in a margin of safety. As shown in Part til [of the application dated April 25,1996), incorporation of the proposed change involves an insignificant reduction in the margin of safety (less than a one percent increase in the baseline core damage frequency (2.84E-05/yr), which is considered to be insignificant relative to the underlying uncertainties involved with PSA).
Also, the proposed changes do not significantly reduce the basis for any technical ,
specification related to the establishment of, or the maintenance of, a safety margin nor do l they require physical modifications to the plant. An additional condition is added requiring the SBO-DG to remain operable, in addition to the operable EDG associated with the redundant train while in the 14-day EDG AOT. The PSA results showed that the risk contribution of extending the AOT for an inoperable EDG is insignificant. Also, the reduction in the AOT for the SUT should improve availability thereby reducing overall risk with no reduction of the safety margin. Moreover, the proposed changes affect neither the way in which the EDGs perform their safety function nor the bases for their LCOs.
As previously stated, implementation of the proposed changes is expocted to result in an insignificant increase in: (1) power unavailability to the emergency buses (given that a loss of offsite power has occurred), and (2) core damage frequency. Implementation of the proposed changes does not significantly reduce a margin of safety.
Conclusion:
The above analysis of no significant hazard consideration determination satisfies the three standards of 10 CF 50.92(c). The above proposed changes have been prepared to utilizu the diversity of AC power and preserve the validity of the safety analysis while providing sufficient flexibility in the limiting condition of operability to accommodate the need for maintenance and surveillance of equipment. These proposed changes have been reviewed and approved by the Operations Review Page 3 of 4
Committee and reviewed by the Nuclear Safety Review and Audit Committee at PNPS.
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